CN111781718A

CN111781718A - Far field correction long working distance microscope structure used under overweight environment

Info

Publication number: CN111781718A
Application number: CN202010689885.6A
Authority: CN
Inventors: 谢洪波; 孙毅轩; 杨童; 杨磊; 李锦程
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2020-10-16
Anticipated expiration: 2040-07-17
Also published as: CN111781718B

Abstract

The invention discloses a far field correction long working distance microscope structure used in an overweight environment, wherein an observation sample can be fixed in a sample clamp, the sample can be focused in one dimension in the Z-axis direction through an electric objective table and can move freely in a two-dimensional observation plane, and the microscope can be remotely controlled to realize remote observation. The microscope structure provided by the invention comprises a coaxial light source uniform illumination part, a three-axis electric objective table part with a gantry structure, a fixed-focus objective microscopic imaging part and an ultra-clear camera receiving and outputting part. The illumination part adopts the coaxial illumination mode, and the stroboscopic exposure of illumination light source and the single frame of super clear camera shoot synchro control, but the removal of electronic displacement objective table remote control sample. The structure of the invention has stable mechanical structure, high magnification, long net working distance and clear imaging resolution.

Description

Far field correction long working distance microscope structure used under overweight environment

Technical Field

The invention relates to the technical field of microscopic imaging, in particular to a far-field correction long-working-distance microscope structure used in an overweight environment.

Background

With the continuous progress of science and technology, the sample scale researched by scientific experiments is more and more microscopic, and the required experimental environment is more and more special. This requires that the microscope used as the observation device in the experiment has a larger magnification, and the microscope has a more stable mechanical structure and is less susceptible to the experimental environment.

At present, most of mechanical structures of microscopes are straight cylinder type, materials are mostly common alloys, a large number of gaps and movable assemblies exist inside machinery, and the bearing capacity of the mechanical structure of the whole microscope is poor. Therefore, the common microscope structure can cause mechanical deformation due to self weight increase in an overweight environment, the locking function of the movable component can be out of order due to overlarge pressure, and finally, the imaging light path of the microscope is damaged, so that the microscope cannot normally work in the overweight environment.

For a microscope objective, the working distance of the objective is related to the focal length of the objective, and the shorter the focal length of the objective, the larger the magnification, and the shorter the working distance. Thus, long working distances are sacrificed if one wants to use high power microscope objectives. However, in some special experimental environments, such as laser processing or microfluidic chip observation, the state of the sample needs to be interfered and changed while the sample is observed, which requires a longer working distance to increase the working space. Therefore, the short working distance of the objective lens and the long working space of the sample become a contradiction to be solved in the special environment of the microscope.

At present, the overweight environment required in the experiment is mostly obtained by using a centrifuge rotating at a high speed, so that the microscope can generate overall vibration due to the vibration of the centrifuge in the experiment process, and the vibration becomes obvious under a high magnification even if the vibration is very small. If a light source with long-time continuous exposure is adopted, the image captured by the camera generates smear, and the observation effect is influenced.

Disclosure of Invention

Based on the known prior art, the present invention provides a long working distance far field correction microscope structure for use in an overweight environment, which is used for observing a sample chip in the overweight environment and allowing a longer working distance.

In order to realize the purpose of the invention, the far-field correction long-working-distance microscope structure used in the overweight environment comprises a coaxial light source light-homogenizing illumination part, a gantry structure triaxial electric objective table part, a fixed-focus objective microscopic imaging part and an ultraclean camera receiving and outputting part, wherein the coaxial light source light-homogenizing illumination part adopts a coaxial illumination mode, and the stroboscopic exposure of an illumination light source and the single-frame shooting of the ultraclean camera are synchronously controlled;

the coaxial light source uniform illumination portion includes: the device comprises a light source, a beam splitter prism structure, a turning light path structure, a long-distance far-field correction micro objective and a micro objective fixing frame, wherein the light source consists of an optical fiber collimator and an optical fiber fixing frame;

the three-axis electric objective table part of the gantry structure comprises: the device comprises a sample clamp, a sample clamp fixing plate, a displacement table A, a displacement table B, a displacement table C, a displacement table D, a displacement table connecting plate I and a displacement table connecting plate II, wherein the displacement table A and the displacement table B are fixed at two ends of the displacement table connecting plate I and jointly control the displacement of a sample in the Z-axis focusing direction; the displacement table C is fixed on the upper part of the displacement table connecting plate I and controls the displacement of the sample in the X-axis direction; the displacement table D is fixed on the displacement table C through a displacement table connecting plate II, the displacement of the sample in the Y-axis direction is controlled, the sample is observed to be fixed in the sample clamp, and the sample clamp is fixed on the displacement table D through a sample clamp fixing plate;

the fixed focus objective microscopic imaging part comprises: the microscope comprises a turning light path structure, a far-field correction long-working-distance microscope objective and a microscope objective fixing frame, wherein the turning light path structure consists of a sleeve lens, a reflecting prism and an imaging light path cover plate;

the ultra-clear camera receiving output part comprises: the ultra-clear industrial camera comprises a light splitting prism structure, an ultra-clear industrial camera and an industrial camera fixing frame, wherein the light splitting prism structure is composed of a light splitting prism, a fixing frame and a coaxial light path cover plate, imaging light rays emitted from an imaging part penetrate through the light splitting prism in the light splitting prism fixing frame and then irradiate onto a detector target surface of the ultra-clear industrial camera fixed on the industrial camera fixing frame, and the coaxial light path cover plate is used for preventing stray light in an observation environment from entering an imaging light path.

Wherein, the diagonal dimension of the ultra-clear camera detector is 1.1 inches, and the ultra-clear camera detector has the resolution of 4K ultra-clear.

The displacement table of the three-axis electric objective table part of the gantry structure can be remotely controlled to move.

Wherein, microobjective and sleeve lens all adopt standard screwed interface to design, dismantle the convenience, easily change.

In addition, the micro objective adopts titanium alloy as a mechanical shell material, the lens barrel is assembled seamlessly, and all movable components are removed, so that the displacement and vibration generated by an overweight environment are synchronized, the relative displacement between the lenses is reduced, and the imaging stability is ensured.

Compared with the prior art, the invention has the advantages that,

firstly, a coaxial light source scheme is adopted for illumination, and uniform illumination with peak power of more than 200W can be finally obtained; the objective table adopts a gantry structure, and a stable three-axis electric remote control objective table can be obtained finally; the objective lens is designed independently, and finally the far-field correction type long-working-distance microobjective with the net working distance of 10mm and the focal length of 4mm can be obtained; the ultra-clear camera detector has a diagonal dimension of 1.1 inches and has a resolution of 4K ultra-clear.

Secondly, after the pulse laser emitted by the Q-switched pulse laser passes through a coaxial light source illumination part of the microscope objective, an illumination light beam with uniform energy distribution emitted in a collimated mode can be obtained, an illumination light spot on the surface of a sample can completely cover the range of the sample observed by the microscope objective, and the microscope objective has the advantages of uniform illumination, large light intensity and high energy utilization rate.

And thirdly, the electric displacement tables used by the three-dimensional electric object stage are driven by the stepping motors with the high-power speed reducers, so that the rotating speed of the motors is reduced as much as possible, the torque is increased, the driving force of the displacement tables is finally increased, the motors can still normally work even under an overweight environment, and the spatial positions of samples can be controlled and moved. In addition, the speed reducer can also improve the minimum resolution of the stepping motor, finally can reach the minimum stepping resolution of half pulse 1 μm and full pulse 2 μm, and can ensure the integrity of sample observation when moving the sample.

And finally, designing the microscope objective by adopting an imaging light path of far-field correction. The final magnification of the microscope is obtained from the ratio of the focal length of the microscope objective and the focal length of the telescopic lens. Therefore, the microscope objective lenses with different focal lengths and the sleeve lenses with different focal lengths can be combined, so that the amplification effects with different magnifications can be obtained.

In addition, in order to solve the image smear generated by the vibration of the centrifuge, a technical method of shortening the exposure time is selected and adopted finally. But if the exposure of the light source and the camera shot are not synchronized, a lack of images occurs. Therefore, a synchronous control circuit for illumination and imaging is designed, so that the camera is ensured to acquire images during light source exposure, and clear amplified images can be obtained during each frame of shooting.

Drawings

FIG. 1 is a schematic top view of a microscope structure according to the present invention;

FIG. 2 is a schematic view of a structure of a turning optical path provided by the present invention;

FIG. 3 is a schematic view of a beam splitter prism according to the present invention;

FIG. 4 is a schematic view of a light source structure provided by the present invention;

FIG. 5 is a schematic view of an axial structure of a microscope according to the present invention;

FIG. 6 is a schematic diagram of the operation of the uniform illumination part of the coaxial light source;

FIG. 7 is a schematic diagram of a basic structure of a three-axis electric stage part of a gantry structure;

FIG. 8 is a schematic diagram of the operation of the fixed focus objective microscopic imaging part and the receiving and outputting part of the ultra-clear camera.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in figures 1-8 of the drawings,

the embodiment provides a far-field correction long-working-distance microscope structure used in an overweight environment, which comprises a coaxial light source uniform illumination part, a three-axis electric objective table part of a gantry structure, a fixed-focus objective microscope imaging part and an ultraclean camera receiving and outputting part.

Wherein, coaxial light source even light illumination part includes: the device comprises a light source 1, a beam splitter prism structure 4, a turning light path structure 7, a far-field correction long-working-distance microscope objective 21 and a microscope objective fixing frame 22, wherein the light source 1 consists of an optical fiber collimator 2 and an optical fiber fixing frame 3; the beam splitting prism structure 4 consists of a beam splitting prism, a fixing frame 5 and a coaxial light path cover plate 6; the turning light path structure 7 is composed of a sleeve lens 8, a reflecting prism 9 and an imaging light path cover plate 10.

Wherein, gantry structure triaxial electric objective table part includes: sample grip 11, sample grip holding plate 12, displacement stage a13, displacement stage B14, displacement stage C15, displacement stage D16, displacement stage attachment plate I17, and displacement stage attachment plate I I18.

Wherein, the microscope imaging part of the fixed focus objective comprises: the device comprises a turning light path structure 7, a far-field correction long-working-distance microscope objective 21 and a microscope objective fixing frame 22, wherein the turning light path structure 7 consists of a sleeve lens 8, a reflecting prism 9 and an imaging light path cover plate 10.

Wherein, super clear camera receives output part includes: the system comprises a light splitting prism structure 4, an ultra-clear industrial camera 19 and an industrial camera fixing frame 20, wherein the light splitting prism structure 4 is composed of a light splitting prism, a fixing frame 5 and a coaxial light path cover plate 6.

The principle schematic diagram of the dodging illumination part of the coaxial light source designed according to the design principle is shown in fig. 6. The Q-switched pulse laser is used as an incident light source 1 of a microscope, and homogenized laser is input into an optical fiber collimator 2 after being transmitted by a light-homogenizing multimode optical fiber. The optical fiber collimator 2 performs collimation and beam expansion processing on the homogenized laser to obtain a collimated and emergent uniform light beam. The light beam is reflected by the beam splitter prism and then enters the sleeve lens 8, the sleeve lens 8 focuses the light beam, and the emergent light is reflected by the two reflecting prisms 9 and then enters the long-working-distance correcting microscope objective lens 21. The optical path between the sleeve lens 8 and the farfield correction long-working-distance microscope objective lens 21 is the sum of the back focal lengths of the sleeve lens 8 and the farfield correction long-working-distance microscope objective lens 21, so that the light beam emitted from the sleeve lens 8 is converged to the back focal point of the sleeve lens 8 and then is diverged. And the back focus of the telescopic lens 8 is superposed with the back focus of the long-working-distance farfield correction microobjective 21, so that the diffused light beams can be emitted as parallel light after passing through the long-working-distance farfield correction microobjective 21. Thus, a homogenized and parallel illumination beam can be finally obtained, which is perpendicularly irradiated to the surface of the observation sample mounted on the sample holder 11.

The basic structure of the three-axis electric stage part of the gantry structure designed according to the design principle is shown in fig. 7. The displacement table A13 and the displacement table B14 are fixed at two ends of a displacement table connecting plate I17 and are used as upright posts of a gantry structure to jointly control the displacement of the sample in the front and back focusing directions. In general, one of the two guide rails of the gantry structure is a driving guide rail, and the other guide rail is a driven guide rail, but in an overweight environment of high-speed rotation, if the control is performed in this way, the displacement table is not easy to control due to the influence of overweight, and distortion and inclination are generated. Therefore, a double-active guide rail form is required to be adopted, the positions of two upright posts of the gantry structure can be controlled, and the displacement generated by vibration and centrifugal force is reduced. The displacement table C15 is fixed on the upper part of the displacement table connecting plate I17 and is used as a beam of a gantry structure for controlling the displacement of the sample in the left and right directions. The displacement table D16 is fixed on the displacement table C15 through a displacement table connecting plate II18, and controls the displacement of the sample in the vertical direction. The sample chip is held in the sample holder 11, and the sample holder 11 is held on the displacement stage D16 via the sample holder holding plate 12. The sample is wrapped up completely and is fixed inside sample holder 11, can guarantee that the sample does not drop in the observation process, and the not random removal guarantees that the formation of image is clear.

The schematic diagram of the microscope imaging part of the fixed focus objective designed according to the design principle is shown in FIG. 8. Firstly, a microscopic objective 21 with far field correction and long working distance is used for imaging an observed sample, and because the microscopic objective adopts a far field correction working form, emergent imaging light rays are parallel light, the rear working distance of the microscopic objective can be randomly selected within a certain optical path range, and therefore, the optical path distance of the microscopic objective can be selected to be the same as that of an illumination part. The light emitted from the microscope objective is reflected twice by the two reflecting prisms 9 and then enters the sleeve lens 8, the sleeve lens 8 converges the imaging light, the emitted light enters the receiving and outputting part of the ultraclean camera and passes through the beam splitter prism used by the illuminating part, and finally a clear amplified sample image is obtained on the detector target surface of the 4K ultraclean CCD camera.

To ensure that the image taken by the camera is clear and free of smear, the exposure time of the sample must be reduced. Therefore, a Q-switched pulse laser with the pulse width of 5ns is finally adopted as the illumination basic light source 1, and the vibration of the sample is ensured not to cause the image jitter. In order to ensure that the exposure time of the pulse laser and the shooting time of the camera captured image are synchronized, the mode of using synchronous external triggering for the pulse laser and the camera captured image is finally decided to be controlled. The same signal generator is used for outputting two beams of same square wave signals, and one beam of signal is used for controlling the passive Q-switching of the laser so that the laser emits pulses when the signal rises; the other beam is used to control the single frame capture of the camera so that it captures an image at the rising edge of the signal. The light source exposure and the camera shooting can be completely synchronized only by testing the response time of the two square wave signals and slightly adjusting the time difference of the two square wave signals when the device is used.

The technical means not described in detail in the present application are known techniques.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A far-field correction long-working-distance microscope structure used in an overweight environment is characterized by comprising a coaxial light source light-homogenizing illumination part, a three-axis electric objective table part of a gantry structure, a fixed-focus objective microscope imaging part and an ultra-clear camera receiving and outputting part, wherein the coaxial light source light-homogenizing illumination part adopts a coaxial illumination mode, and the stroboscopic exposure of an illumination light source and the single-frame shooting of the ultra-clear camera are synchronously controlled.

2. The structure of claim 1, wherein a remote control function is added to the displacement stage of the triaxial electric stage of the gantry structure to solve the problem that the laboratory personnel cannot move the stage on site due to the harsh experimental environment, so as to ensure that the laboratory personnel can be kept away from the harsh and dangerous experimental environment and the moving of the sample is safer and more convenient.

3. The structure of claim 1, wherein the microscope objective barrel, the optical path, and the camera support are made of titanium alloy, and the barrel is assembled seamlessly without any moving components to ensure the mechanical deformation of the microscope under the overweight environment is within the tolerance range.

4. The infinity corrected long working distance microscope configuration for use in an overweight environment according to claim 1 wherein the microscope objective is designed with a infinity corrected imaging optical path.